This invention relates to check valves, particularly unidirectional fluid flow valves useful for admitting fuel into combustion chambers of internal combustion engines. In particular, the invention may be used to admit fuel into pre-combustion chambers. For this application such a valve replaces a fuel injection valve and utilizes the pressure differential between a pre-combustion chamber and a pre-combustion chamber fuel manifold of an engine to meter and control the fuel injection timing thereof.
For a more complete discussion of these valves incorporated by reference is U.S. Pat. No. 4,531,543 issued July 30, 1985 to George L. Markley. Use of the invention as disclosed and claimed in the above U.S. patent is effective, except that the invention makes use of a valve element defining an orifice, which may occasionally fail to or may not operate smoothly. This is because of a stickiness between a valve housing and the element due to moisture build-up and/or cocking of the element within the valve.
Also, during certain times of the engine cycle, when there is little or no pressure differential between the inlet of the valve and the communicating adjacent pre-combustion chamber, the valve element tends to float. Such a phenomenon allows low volume fluid flow in either direction at a time when the valve would preferable be closed. Fuel flow toward the pre-combustion chamber (or power cylinder) at this time decreases the exactness of fuel admission control. Flow away from the pre-combustion chamber would likely contain gases contaminated by combustion particles that would foul the clean valve seat, raise the valve temperature, and displace fuel gas in the supply line effecting the next admission cycle.
It has also been found that the use of certain seals required within the preferred embodiment of the disclosed patented invention as aforecited adds certain volumes of space within the valve. This space contributes to the volume of heated gases compressed within the valve during the combustion cycle which increases the valve's temperature. Other undesirable features of the seals are additional assembly time, extra cost, and occasional failure. Finally, for proper operation, one of these seals must be thinner than the valve element, thereby limiting how thin, lightweight, and flexible the valve element can be made. These parameters may effect the responsiveness of the valve.
Furthermore, assembly of the valve disclosed in the above-referenced patent prove difficult as the internal components of the valve have to be critically positioned with the valve housing. The numerous valve components, when being positioned within the valve housing annoyingly hang up on threading within the valve housing and become disoriented. Therefore, extra labor and tools are needed to insure that the components are properly aligned when assembled.
There is substantial interest in the area of valve manufacture and use to develop a unidirectional fluid flow check valve assembly which avoids the abovementioned problems.
The features identified above as being desired for a unidirectional fluid flow check valve assembly are all provided by the present invention.